@Mahitha The Microsoft.ServiceBus namespaces/queues section remains same for both standard and premium namespace. The document has the description of the object and name that are supported.
For your reference I have created the ARM template using the document which creates the premium namepace and one queue under your premium namespace. You can modify it as per your requirement.
To define the Max message size (in KB) you need to define
maxMessageSizeInKilobytes in your ARM template. I have reached out to the docmentation team to reflect the same.
Update 9/30: The document changes are reflected in the latest API version 2021-06-01-preview. Please leverage the latest API version.
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